OBC calibration

[M Blitz]

I'm trying to retrofit an OBC on a 1983 528e, and the average mpg and mph are totally off. Does any have info on (re)calibrating the OBC?

[MannyE]

Make sure you have the correct coding plug.

[M Blitz]

I do.

[John in VA]

There is a small adjustment screw located behind a plastic cover in the lower left hand corner of the OBC. When the low fuel light first comes on (the warning light in the fuel gauge), the tank should have 4.5 liters of fuel left (I'm not entirely sure about this value - others on the UUC digest have suggested that the proper value is more like 6.5 liters, so who knows). Make sure the car is parked on a level surface, and then turn the little screw until the display reads 4.5L.

[Blue Shadow]

There is a small adjustment screw located behind a plastic cover in the lower left hand corner of the OBC.

This is for the OBC II. I expect the op in an 83 has the earlier one but he did not state OBC II and is retrofitting the unit so unknown which one specifically as the II was very common the earlier one not so much.

The manual says 1.8g or 7l is the illumination point in the later E28 owner's manual. The ZA E23 manual says just shows a range of kilometers. 1.8g converts to 6.81 liters so your 6.5 is as accurate as BMWs conversion.

[M Blitz]

Sorry for the lack of specificity. The OBC came from a 1987 535i, so I would assume that John in VA's comment/instruction applies.

I'll give that a try.

Thank you gents!

[M Blitz]

The manual says 1.8g or 7l is the illumination point in the later E28 owner's manual. The ZA E23 manual says just shows a range of kilometers. 1.8g converts to 6.81 liters so your 6.5 is as accurate as BMWs conversion.

How can I get my hands on this manual, is it the TIS?

Thanks

[Blue Shadow]

Bottom of the left column

http://www.e38.org/e23/